The investigators will examine the effectiveness, cost-effectiveness, feasibility, and acceptability of an enhanced community health worker intervention and outreach system for pregnant women to facilitate early and consistent ANC attendance, early and effective PMTCT uptake, with the aim to further reduce mother-to-child transmission of HIV. We will test the effectiveness hypothesis in a cluster-randomized controlled trial; the unit of randomization is the administrative unit of a ward, which is the geographical unit below a district in the Tanzanian government system. We randomly allocate all 60 wards in two of the three districts in Dar es Salaam, Tanzania -- Kinondoni and Ilala districts -- to receiving the enhanced community health worker intervention and outreach system vs. receiving the standard of care in the Tanzanian public-sector health system.